When treating a human or animal body, it can be presumed that the treatment instrument will be contaminated with disease-causing agents originating from the body. This applies both to such treatment instruments with which the body can be treated at a distance, for example spray nozzles, and in particular to such treatment instruments during the use of which direct contact occurs with the body. In particular contamination of the treatment instrument can be reckoned with when the treatment instrument comes into contact with body fluids, for example blood, as is the case in particular in the case of treatment with a surgical treatment instrument.
It is therefore the intention to sterilize the treatment instrument including its supply hose, through which the necessary driving energy and, if applicable, a treatment agent, in particular a coolant or the like, are fed.
The hand piece of a treatment instrument can consist of a drive portion with a fixedly installed motor and a tool carrier portion, it being possible to couple the drive portion and the tool carrier portion together in a releasable manner. Various tool carrier portions, predestined for respective treatments, can thus be selectively connected with the drive and be detached again.
For the purposes of sterilization, steam sterilization at up to 3 bar pressure at a temperature of 145.degree. C., for example, is usual.
A complicated construction of the motor and of the receiving portion which receives it at the drive portion is required for a sterilization-proof construction of the motor, as otherwise sterilizing agent is able to penetrate into the motor which impairs the bearing and functional parts which are present and thus substantially reduces the life of the treatment instrument. A construction of the motor which is absolutely secure against entry of sterilizing agent is difficult and expensive, so high costs of production have to be reckoned with.